Mitsubishi Denki Kabushiki Kaisha

Hideki Igarashi

Naohito Tomoe

A diversity receiver includes: a differential detection diversity reception circuit for performing a diversity reception with employment of a differential detection to thereby output hard decision data thereof; a least-squares combining diversity reception circuit for performing a least-squares combining diversity reception to thereby output differentially decoded result of the hard decision data; a selection control circuit for producing a selection control signal used to select one of the hard decision data outputted from the differential detection diversity reception circuit and the differentially decoded result outputted from the least-squares combining diversity reception circuit based upon a predetermined selection basis; and a selection circuit for selecting one of the hard decision data and the differentially decoded result based upon the selection control signal.

Diversity receiver

An adaptive equalizer includes a channel memory length estimator (,) for estimating a channel memory length of a received signal, an adaptive equalizer (,) for reducing effect of intersymbol interference on the received signal using a technique suitable for a channel with a fast time-varying characteristic, an adaptive equalizer (,) for reducing effect of intersymbol interference on the received signal using a technique suitable for a channel with a large delay spread, and a selector for switching, in response to the channel memory length supplied from the channel memory length estimator (,), between the adaptive equalizer (,) suitable for the channel with the fast time-varying characteristic and the adaptive equalizer (,) suitable for the channel with the large delay spread, thereby implementing good bit error rate performance.

Adaptive equalizer and adaptive equalization scheme

A soft decision decoder including an adaptive equalizer and a reliability information generator. The reliability information generator, receiving soft decision data and equalized square error from the adaptive filter, performs delay detection of the soft decision data, and then rotates the phase of the delay detected data so as to match the data to transmitted data components. The rotated data is weighted with the average value of the equalized square error to generate the reliability information for the soft decision Viterbi decoding. This makes it possible to obviate the exponential or logarithm calculations which are conventionally needed for generating the reliability information for carrying out the soft decision Viterbi decoding of the output of the adaptive equalizer, and hence to reduce the enormous amount of calculations and the size of hardware like DSP for performing the calculations.

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Tokyo, Japan

Hideki Igarashi